The invention relates to a mounted optical component and also a method for the production of mounted optical components. Furthermore, the invention relates to the use of mounted optical components.
In a standard manner, optical components are mounted or clamped by means of a form-fit and frictional fit. Alternatively and of particular interest for small or very sensitive components, integral methods, predominantly glueing, can be used. If polymer-based adhesives require to be replaced by inorganic joining media because of particular conditions of use, soft solder alloys are possible.
In order that soft solder alloys can be applied as joining medium, it is necessary to produce wettable metallisations, e.g. by vacuum coating or sputtering on the joining geometries of the components and the mounting. The wettable layer can be provided at the same time with the solder material as thin-film system, alternatively solder is applied as a discrete volume. The melting is effected by means of laser since the energy input must be effected locally and temporally discretely in order not to destroy sensitive optical components. Melting of the solder by standard reflow processes is ruled out because of the cleanliness requirements of the lens system and also because of the generally greatly differing thermal coefficients of expansion of component and mounting, which would lead to impermissible thermomechanical stresses during global heating of the assembly to be joined.
In the past, the greatly differing heat conductivity of the two partners to be joined, optical component and mounting, has proved to be critical for the laser soldering process. Because of the high temperature gradient in the mounting material which generally has a high to very high thermal conductivity, the process must take place in general with high laser powers in order to enable local heating and hence wetting. This is at variance with the requirement to keep the laser power as low as possible in order not to damage the poorly heat-conducting, optical component. Correspondingly, joining places of lens systems to mountings made of metal or ceramic have to date been very difficult to control when using solder as joining medium and the laser as energy source for the melting.
The underlying object is the joining of optical components, i.e. lenses, mirrors, prisms etc., made of a generally glass-like, poorly heat-conducting material, in a mounting (optomechanical component, generally made of readily heat-conducting material, such as metal or ceramic, for incorporation of the optical component in the overall system) by means of the integral joining method, “soldering”.
This object is achieved by the mounted optical component having the features of claim 1. Claim 11 relates to a method for the production of a mounted optical component and claim 14 to the use of mounted optical components. The further dependent claims reveal advantageous developments.